The U.S. Senate, in a bipartisan 73-21 vote, moved Thursday to preserve 2 million acres in nine states as wilderness areas — including 315,000 acres in Colorado.

Among the areas in the largest expansion of the country’s wilderness lands in 15 years are parts of Rocky Mountain National Park and Dominguez and Escalante canyons.

“This confers the highest level of protection on these lands,” said Steve Smith, assistant regional director of the Wilderness Society.

“Everyone thinks it’s a national park so it’s protected, but this will keep 250,000 acres as untouched wilderness,” Smith said.

The bill, which goes to the House of Representatives for a final vote, also creates a 210,000-acre national conservation area around Escalante and Dominguez canyons south of Grand Junction, including a 65,000-acre wilderness area.

“This has been a long time coming,” said Roger Singer, western regional representative for the Sierra Club. “But now some of the most beautiful places in Colorado will be protected for generations.”

The Independent Petroleum Association of Mountain States expressed concern that the wilderness and heritage areas will place more land out of bounds for energy development.

Sen. Tom Coburn, R-Okla., the bill’s chief opponent, said it was a land grab.

“We’re going to trample on property rights like we haven’t in decades,” he said.

In addition to the wilderness areas, the bill helps Colorado water projects and designates parts of South Park and the San Luis Valley as National Heritage Areas.

“This is a recognition of the cultural contributions of the settlers who helped make Colorado what it is,” said the Sierra Club’s Singer.

The South Park National Heritage Area would protect 19 working ranches.

The Sangre de Cristo National Heritage Area — covering part of Conejos, Costilla and Alamosa counties — is being recognized as the confluence of American Indian, Latino and Anglo cultures.

The bill also would create the Front Range Mountain Backdrop Act — directing the U.S. Forest Service to work with Front Range communities to protect open spaces around the Arapaho-Roosevelt National Forest.

Sen. Ken Salazar, who is the nominee for interior secretary — was a sponsor of the park wilderness bill.

“This bill represents years of work by a broad range of stakeholders . . . to find a sensible way to permanently protect the park’s backcountry while protecting water rights and water infrastructure,” Salazar said.